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<div class="titlepage"><div><div><h3 class="title">
<a name="boost_asio.reference.DynamicBuffer_v2"></a><a class="link" href="DynamicBuffer_v2.html" title="Dynamic buffer requirements (version 2)">Dynamic buffer
      requirements (version 2)</a>
</h3></div></div></div>
<p>
        A dynamic buffer encapsulates memory storage that may be automatically resized
        as required.
      </p>
<p>
        A dynamic buffer type <code class="computeroutput">X</code> shall satisfy the requirements of <code class="computeroutput">CopyConstructible</code>
        (C++ Std, [copyconstructible]) types in addition to those listed below.
      </p>
<p>
        In the table below, <code class="computeroutput">X</code> denotes a dynamic buffer class, <code class="computeroutput">x</code>
        denotes a value of type <code class="computeroutput">X&amp;</code>, <code class="computeroutput">x1</code> denotes values
        of type <code class="computeroutput">const X&amp;</code>, <code class="computeroutput">pos</code> and <code class="computeroutput">n</code> denote
        values of type <code class="computeroutput">size_t</code>, and <code class="computeroutput">u</code> denotes an identifier.
      </p>
<div class="table">
<a name="boost_asio.reference.DynamicBuffer_v2.t0"></a><p class="title"><b>Table 13. DynamicBuffer_v2 requirements</b></p>
<div class="table-contents"><table class="table" summary="DynamicBuffer_v2 requirements">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  expression
                </p>
              </th>
<th>
                <p>
                  type
                </p>
              </th>
<th>
                <p>
                  assertion/note<br> pre/post-conditions
                </p>
              </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput">X::const_buffers_type</code>
                </p>
              </td>
<td>
                <p>
                  type meeting <a class="link" href="ConstBufferSequence.html" title="Constant buffer sequence requirements">ConstBufferSequence</a>
                  requirements.
                </p>
              </td>
<td>
                <p>
                  This type represents the underlying memory as a sequence of @c
                  const_buffer objects.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">X::mutable_buffers_type</code>
                </p>
              </td>
<td>
                <p>
                  type meeting <a class="link" href="MutableBufferSequence.html" title="Mutable buffer sequence requirements">MutableBufferSequence</a>
                  requirements.
                </p>
              </td>
<td>
                <p>
                  This type represents the underlying memory as a sequence of @c
                  mutable_buffer objects.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x1.size()</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">size_t</code>
                </p>
              </td>
<td>
                <p>
                  Returns the size, in bytes, of the underlying memory.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x1.max_size()</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">size_t</code>
                </p>
              </td>
<td>
                <p>
                  Returns the permitted maximum size of the underlying memory.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x1.capacity()</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">size_t</code>
                </p>
              </td>
<td>
                <p>
                  Returns the maximum size to which the underlying memory can grow
                  without requiring reallocation.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x1.data(pos, n)</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">X::const_buffers_type</code>
                </p>
              </td>
<td>
                <p>
                  Returns a constant buffer sequence <code class="computeroutput">u</code> that represents
                  the underlying memory beginning at offset <code class="computeroutput">pos</code>, and
                  where <code class="computeroutput">buffer_size(u) &lt;= n</code>.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x.data(pos, n)</code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput">X::mutable_buffers_type</code>
                </p>
              </td>
<td>
                <p>
                  Returns a mutable buffer sequence <code class="computeroutput">u</code> that represents
                  the underlying memory beginning at offset <code class="computeroutput">pos</code>, and
                  where <code class="computeroutput">buffer_size(u) &lt;= n</code>.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x.grow(n)</code>
                </p>
              </td>
<td>
              </td>
<td>
                <p>
                  Requires: <code class="computeroutput">size() + n &lt;= max_size()</code>.<br> <br>
                  Extends the underlying memory to accommodate <code class="computeroutput">n</code> additional
                  bytes at the end. The dynamic buffer reallocates memory as required.
                  All constant or mutable buffer sequences previously obtained using
                  <code class="computeroutput">data()</code> are invalidated.<br> <br> Throws: <code class="computeroutput">length_error</code>
                  if <code class="computeroutput">size() + n &gt; max_size()</code>.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x.shrink(n)</code>
                </p>
              </td>
<td>
              </td>
<td>
                <p>
                  Removes <code class="computeroutput">n</code> bytes from the end of the underlying memory.
                  If <code class="computeroutput">n</code> is greater than the size of the underlying memory,
                  the entire underlying memory is emptied. All constant or mutable
                  buffer sequences previously obtained using <code class="computeroutput">data()</code>
                  are invalidated.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput">x.consume(n)</code>
                </p>
              </td>
<td>
              </td>
<td>
                <p>
                  Removes <code class="computeroutput">n</code> bytes from the beginning of the underlying
                  memory. If <code class="computeroutput">n</code> is greater than the size of the underlying
                  memory, the entire underlying memory is emptied. All constant or
                  mutable buffer sequences previously obtained using <code class="computeroutput">data()</code>
                  are invalidated.
                </p>
              </td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break">
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 2003-2021 Christopher
      M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
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